Process for improving the transparency of glassine paper



Sept. 5, 1933. J. E. KIEFER 1,925,448

PROCESS FOR IMPROVING THE TRANSPARENCY OF GLASSINE PAPER Filed July 21,1930 1 g INVENTOR.

BY W W gzw vfl, EMA

ATTORNEY.

Patented Sept. 5, 1933 UNITED STATES PROCESS FOR IMPROVING THE TRANS-PARENCY OF GLASSINE PAPER Julius E. Kiei'er, Milwaukee, Wis.,.assignorto Transcello Paper Company, Milwaukee, Wis., a corporation of WisconsinApplication July 21, 1930. Serial No. 469,346

1 Claim.

The invention relates to a process for improving the transparency ofglassine paper.

Glassine paper, as is well known, is a smooth hard paper, and I findthat byv merely coating such paper with a transparent liquid that thetransparency of the paper itself is not greatly improved, but that inorder to obtain the best effect, it is necessary to provide a processwhich contemplates a coating of both sides of the paper and animpregnation or penetration of the paper by the transparent liquid, suchas a suitable resinous vsolution capable of penetrating the paper, andto this end the object of this invention is to provide a process whereinthe paper to be treated is immersed in the bath of this solution for asufiicient length of time to enable the solution to thoroughly penetrateand impregnate the paper, and then the paper so treated is run through aset of squeeze rolls held together under pressure 2 so as to remove theexcess solution from the impregnated paper, and to further augment theimpregnation of the paper with the solution, after which the paper isdried preferably under tension.

The invention further consists of the method and steps of the methodhereinafter set forth, and

more particularly defined by the claim at the conclusion hereof.

The drawing shows more or less diagrammatically, an apparatus forcarrying out the method embodying the invention.

In the drawing the numeral 2 designates a suitable frame upon which thesupply roll 3 for the glassine paper to be treated is mounted, as isalso a tank 4 that may be adjusted up and down relative to the frame 2by means not shown, and through which the paper is carried by runningthe same over guide rolls 5 and 6, the guide roll 6 being mounted onsupporting arms '7 preferably adapted to be adjusted to differentelevations in the tank so as to position the guide roll 6 at differentdistances from the bottom of the tank to thereby vary the length oftravel of the paper through the bath 8 of treating material. From thedrawing it will be noted that the paper from the supply roll travelsover the roller 5 andthence around the roller 6 and is then carried upbetween two squeeze rolls 9 and 10. These rolls are adapted throughtheir bearings, to be brought practically in contact with each other,one of the rolls as 9 being cold chilled iron, and the other 10 asuitable rubber roll, whereby the paper passing through these rolls issubjected to the 7 pressure exerted between the rolls.

From squeeze rolls 9 and 10 the treated paper is carried through a hood11 over a suitable driven roll 12 and thence down around a guide roll 13between guide rolls 14, and is wound up on a mandrel 15 which is adaptedto move vertically in slotted guide brackets 16, the winding of thepaper onto the mandrel 15 being efiected by a driven roll 17 connectedby idler roll 18 with another roll 19, the rolls 17 and 19 thus beingrotated in a clock-wise direction to wind up the finished paper on the-mandrel 15 by the frictional engagement between the paper as it iswound up with the rolls 17 and 19, the mandrel 15 being free to move upin the slotted bracket 16 as the size of the roll of finished paperincreases.

A partition 20 is provided in the hood 11, and heated drying air isintroduced into the hood in the direction shown by the arrow 21, passesupwardly to the top of the hood and thence returns on the other side andout through the opening 22. The length of the hood is such that by thetime the treated paper reaches the driven roll 12 it has become dried bythe action of the air passing through the hood.

The solution 8 in the tank 4 is a solution preferably including avarnish gum or other suitable resinous substance of a'character andchemical composition capable of penetrating the glassine paper, the gumor other resinous substance being thinned out to this consistency by theuse of a suitable solvent such as alcohol.

The paper during its travel through the bath is immersed therein for asuflicient period of time so as to enable the solution to thoroughlypenetrate and impregnate the paper and then the paper so treated iscarried through the squeeze rolls 9 and 10 which put pressure upon thesame so as to remove the excess solution, from the treated paper, andfurther act to augment the impregnation of the paper with the solution.This action of the squeeze rolls also has the efiect of leaving only apredetermined amount of the solution as a coating on both sides of thepaper and this facilitates the drying of the same as the paper is passedthrough the drying chamber including the hood 11, and as previously 10onoted the treated paper does not come in contact with any surface untilthe surface of the paper is dry. The length of the tank 4 and the depthat which the lower roll 6 is placed in the tank are so determined as togive a definite period of imm5 mersion depending upon the speed of thepaper run therethrough to thoroughly saturate or impregnate the paperwith the solution. It is also to be noted that the excess material takenoff of the treated paper by the squeeze rolls 9 and 10 5 prove quithaving eaenee flow over these rolls keeps them in a moist condition.

What I claim as my invention is: The methed of treating glassine paperto imthe transparency thereof which consists in r. the paper through abath of transparent w tter in solution to cause

